Boiler.



. L. R. EIVIVIET.

BOILER.

APPLICATION FILED NOV. 26. i913- Patented Aug. Z191?, 2 SHEETS-SHEET l.

S PANT WILLAM L. R. EMMET, OF SCHENECTADY, NEW YORK, ASSGNOB, ,T0 GENERAL ELECTRIC COMPANY, A CORPORATON OF NEW YORK.

BOLER.

Toall whom it may concern.' s

'Be it k'nown that LWILLIAM LR. EMMET, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful improvements in Boilers, ot which the following is a specication.

lThe present invention relates to vapor generators or boilers and has for its object to provide a boiler which is suitable for generating vapor from mercury and which is simple in lconstruction and eicient and reliable in its operation. Owing to the-high boiling point of mercury, about 677 F. at atmospheric pressure, and to its initial cost and weight for a given bulk, the problems presented are radically diderent from those confronting the constructor of a steam boiler. One of the principal problems is that of securing the tubes to the headers. From practical experience l have found that the ordinary expanded joints are not suitable for the reason that they tend to. loosenl through unequal expansion due to large temperature dilerences. In some cases-the stresses due to such expansion are so great as to exceed the elastic limit of the metal employed in certain of the parts.. The high initial cost of mercury and its great weight for a given bulk lead to a construction wherein the storage Ispace is small and hence to the use of a small quan- Vtity of mercury per. unit of output.v Reducing the quantity of mercury, however, necessitates a very active circulation of the liquid since otherwise the output will either be greatly impaired yor the tubes will be damaged by the high temperature of the furnace gases. Still another problem is to conserve all leakage from around the va.- riousl joints and return it to the system for further use. Finally the boiler should be so constructed that it can` be readily assembled and taken down.

For a consideration of what ll believe to be novel and my invention, attention is directed to the accompanying description and claims appended thereto.

ln the accompanying drawings which are illustrative of'my invention, Figure 1 is a view partially in side elevation and .partly in section of a boiler; Fig. 2 is a view in side elevationshowing the arrangement of the boiler tubes and headers; Fig. 3 is\a View in section of one of the boiler ele- Speccation of Letters Patent.

, valve.

Patented Aug.. 7, 121'?.

Application filed vilovein'ner 26, 1913. Serial No. 803,178.

- ments; Figs. d and 5 show means tor uniting the tubes and headers, and Fig. 6 is a cross-sectional view of one of the tubes.

10 indicates the boiler casing lwhich may be made of brick or other suitable material arranged to prevent heat radiation as fully as possible. 11 indicates the fire door.. l may use an oil burner of any suitable construction to heat the boiler or a coal tire may be used if desired. rlhe particular means for supplying the heat is immaterial so long as a sulicient quantity is provided and can be suitably regulated. 12 indicates a stack which creates the necessary draft on the fire and carries'o the burned products of combustion.

Located at a suitable point outside of the boiler casing, as at one side for example, are two `chests 13 and 14, the former containing mercury in liquid form and the latter mercury vapor. rlhe upper chest is en larged to form a vapor containing chamber 15, Fig. 3, which is common to all of the boiler sections or heating units." From the chamber vapor passes by the pipe 16 to a mercury turbine of any suitable construction. The chests are located on the outside of the boiler casing instead of on the inside so as' to reduce as fully as possible the et- 'ects'of expansion and contraction of the parts. The upper and lower chests are connected by a conduit 17 through which liquid mercury can ilow from one to the other. This is also located outside of the boiler casing to reduce the elfects of expansion.

and contraction. The various parts exter-A nal to the casing will commonly be covered by heat-insulating material to prevent undue radiation. The liquid mercury received from the condenser 18 of the turbine flows by the pipe 18a to the lower chest 13 and its admission to the latter is controlled by a valve 1-9. The valve is located at the bottom of a tubular column 20 which is connected at the upper end by the pipe 21 with the vapor chest and at. its lower end by the pipe 22 with the liquid chest. rll`he column is also located outside of the boiler casing so as to prevent ebullition from at ecting the level of the mercury therein. At the upper end of'the column is a oat 23 riding on the mercury contained therein.

' The float is connected 'by a rod 24 with the When the mercury falls below a Y predetermined level the Hoat opens the at all times.

valve and permits liquid mercury to enter from the supply pipe 18a. When theA level is restablished the valve cuts ott' further supply. The float tends to maintain a constant liquid pressure in the lower -chest which will correspond more or less to the level of liquid in the vaporl chest. In practice the valve is usually open to a certain extent and a greater or less amount of mer` cury is flowing past it at all times.

The condenser for the turbine is preferably located above the boiler so that the flow of mercury therefrom to4 the boiler is by ravity. This means that a constant liquid head will be maintained in the boiler ln order to compensate for any loss of mercury in the system due to leakage or other cause, a'reservoir 25 of suitable size isarranged at some point above the boiler and in open communication with the supply pipe 18a. The reservoir has a; sight feed glass or other level indicator 26 on one side so that the attendant can determine bythe mercury level therein whether or not the reservoir is being called on to supplement the supply from the mercury vapor condenser. The mercury in the reservoir will usually stand at about the same level all the time, but it' any leakage takes place in the system, as, at the joints for eX- ample, the level will be lowered, and if necessary the apparatus can be shut down and adjustments or repairs made. lin so far as this feature of my invention is concerned, it is not limited to the particular type of boiler shown.

As before stated, it is of great importance to conserve the supply of mercury and l, therefore, provide boxes or casings for the various joints and connect them with a cooler for condensing the vapor. 27 indicates one of these boxes which .surrounds the flanged joint between the vapor chest 14 and the discharge pipe 16. It is connected by the pipe 28 with the cooler 29.- IThe latter may be of any suitable construction. As shown, it comprises\a closed tank that may be Water or air cooled or both. As shown, cooling Water enters the tank 'by the pipe 29L and leaves by the pipe 29".

lin order to utilize lthe draft of the stack 12 to free the cooler of air and uncondensed gases, the two are connected by the pipe 30. The cooler is provided with a suitable trap` 31 which prevents air from getting into the cooler but permits the condensed mercury to escape to the receptacle 32 from which it can be returned to the system. Other joints in the system are similarly provided with boxes or casings as will be described more in detail later on, and these are connected to the cooler by the pipes 33 which may lead' directly thereto or terminate in a common pipe as shown.l Whether one or more pipes are used will as to contain only a small amount of merrasa-iat depend upon the apparatus.

Referring now to Figs. 2 to 6 inclusive, 35' and 36 indicate the upper and lower headers of a replaceable heating unit oi' which as many may be provided as are necessary to supply the desired 4amount of vapor. These headers are located within the boiler casing and are provided with conduits 37 that extend through the brick cas` ing l0 to the outside. The lower header is provided with a chamber 38 that has an inclined bottom wall so that mercury will drain toward the chest. It is also so shaped the general arrangement oi cury and yet supply it uniformly to all the tubes without undue friction. The header is shown in plan in Fig. 6 and in vcross-section in Fig. 5. lts general shape is rectangular and is relatively long and narrow. The upper header is similarly shaped, the enlargement of the vapor chamber from right to left being to accommodate the vapor and liquid discharged by the numerous parallel arranged tubes. Between the headers is a plurality of seamless steel tubes 39, each of which is of the crossesection shown in Fig. 6. The space between the Walls ofthe tube should be small so as to limit the amount of mercury they will contain. Each tube has a bend, curve, or offset 40 of some character in it between its ends so that under temperature changes the tubes can yield slightly instead of imposing heavy thrusting strains on the headers and possibly injuring the joints and thereby giving rise to l'eakages. The tubes are welded to the headers at 41, Fig. 4, by an acetylene welding torch or other means. They may have only an inside weld or an inside'weld 41 and an outside weld 42, the latter being shown in Fig. 5. The amount of the odset in each tube should be sufficient to permit the parts to move slightly one with respect to the other and prevent un- 110 due strain at the welded joints. The character of the offset can be changed as will readily be appreciated.

The'connections between. the several headers and the liquid chest 13 and the construc- 115 tion of the latter. will now be described. The chest is made of a' forging whichA forms the back, top and bottom walls. rlhe front'wall '43 is formed of relatively thin stock, the

are Welded to the top, bottom' and end walls. The conduits 37 may extend directly into the chests or be provided with removable extensions 44 as shown. The outer end of each extension is edges of which tapered and makes a snug lit in a cone- 125 maaien Vengagedby an adjustable clamping bolt 48.

These bolts pass through a bar 49 and the latter in turn rests on a member 50 which j engagesthe vapor chest. By reason of the `sary or desirable. The designed pressure of the boiler is very low, only a fewv` pounds above atmosphere, so the problem of packing 'against pressure is accordingly a comparatively simple one, except for temperature considerations. Surrounding the conical-seated joint is a box or casing 5l that is snugly fitted to the chest and conduit 44. The lower side of the casing is provided with a recess in which collects the condensed mercury; Connected with this recess is a pipe 33 by means of which any condensed Amercury or leakage vapor may pass to the cooler or to any other suitable point where a definite suction is maintained. The' simplest arrangement is to provide one bx or casing for all the joints but a greater number can be provided if desired. Preferably all ofthe joints are arranged in the same plane to simplify the construction. A material advantage in the construction just described resides in the fact that the joints between the chest and conduits 44 can be tightened from the outside by merely adjusting the nuts on the bolts 47 and 48. The con- Iiections between the vapor chest 14 and theheader 35, and the casing or housing for the conical joints is the same as for the liquid chest and further description seems unnecessary. rlhe chest itself is, however, somewhat different. It comprises a forged or cast por.- tion 52 that extends. along the side of the boiler casing and is provided with a cover 53 that is welded or otherwise secured thereto. The upper and lower chests are mechanically united at their right-hand ends by the pipe 17 which isv provided with an offset to reduce the effects if temperature changes, and at their left-hand ends by the member 54 which also has an yoffset for the same reason. j

As shown, the boiler comprises thirteen replaceable heating units, each of similar construction, .but the 4number can be increased or decreased as desired to meet the conditions of operation. ln order to direct such elements, all of which receive their.

supply of mercury in multiple Afrom the condenser 18 through the conduit-18u. At 56 is shown a branch pipe for supplying mercury to one or more additional boiler elements. common to and makes up for any deficiency in theimercury supply for all of the boiler elements rihe velements will be similarly constructed and each provided with a controlling valve 19 and ioat 23, both located in an outside column arranged as shown.

ln accordance with the provisions of the patent statutes, l have described the principle of operation of my invention, together with the apparatus which li now consider to represent the best embodiment thereof; but I desire to have it understood that the apparatus shown is only illustrative, and that the invention can be carried out by other means'.

What l claim as new Aand desire to secure by Letters Patent of the United States, is

1. ln a mercury boiler, the combination lof a boiler casing, a liquid chest of limited capacity which extends parallel to the casing at the lower portion thereof, a vapor chest of limited capacity which extends parallel to the casing at the upper portion thereof, a curved attened tube connecting said chests, headers connected to said chests and projecting into the boiler casing, and Hattened tubes which areattached at their ends to the headers, each of said tubes being provided with a curved portion between its ends to reduce strains at the points of attachment due to expansion. v 2. in a mercury boiler, the combination of a boiler casing, a vapor 'chest of limited capacity located outside the boiler casing, a liquid chest of limited capacity spaced from the vapor` chest, a tube connecting them, headers arranged in pairs extending from the chests to points inside the boiler casing, tubes within the Vboiler casing connecting said headers, detachable joints vwhich connect said headers to the chests, inclosing means for said joints, and drainage means for said inclosing means.

3. ln a mercury boiler, the combination of vapor and liquid chests, headers arranged in pairs which are detachably secured to the chests, tubes which connect each pair of headers, inclosing means for the joints between one of the chests and the headers connected thereto, and a cooling means that is connected to and receiv the leakage entering said inclosing means.

4. a mercury boiler, the combination of vapor and liquid chests, headers arranged in pairs which are detachably secured to the chests, tubes which connect each pair of headers, a box for the joints between one of the chests and the headers connected thereto, and a suction means acting to withdraw the contents of said box.V

As will be seen the reservoir 25 is joint9 and means for establishing a suction in said box to withdraw leakage vapor and mercury therefrom.

6. In a mercury boiler, the combination of vapor generating elements, a casing therefor, a stack for the Hue gases escaping from the casing, a vapor chest jointed to the element, a box for the joint between the chest and elementa cooler connected to receive leakage from the box, and a conduit leading from the cooler to the stack so that the lat- Ater acts to suck uncondensed gases from the cooler.

. 7. In a mercury boiler, the combination of a plurality of vapor generating elements,

,a chest that is common to the elements and is detachably jointed thereto, a box which is common to all of said joints, and a cooler that is connected to the box and receives leakage therefrom.

mamita 8. ln combination, a boiler for generating mercury vapor, means detachably jointed to said boiler for conveying vapor therefrom, a box for the joint or joints, and coolliong means that receive leakage uid from the 9. ln a boiler of the character described, the combination of a 'vapor generating element, a chest, a detachable joint between the chest and element, a clamping means for said joint, a box inclosing said joint and clamping means, and means outside of the box for adjusting said clamping means.

. ln witness whereof, l have hereunto set my hand this 25th day of November, 1913. 35

WILLIAM L. R. EMMET. 

